Energy can be harnessed directly from the sun, even in cloudy weather. Solar energy is used worldwide and is increasingly popular for generating electricity or heating and desalinating water. Photovoltaics (PV), also called solar cells, are electronic devices that convert sunlight directly into electricity. Solar panels have a lifespan of roughly 30 years, and come in variety of shades depending on the type of material used in manufacturing. Solar PV combines two advantages: module manufacturing can be done in large plants, which allows for economies of scale, and it is also a very modular technology and can be deployed in very small quantities at a time. This allows for a wide range of applications. Systems can be very small, from personal electronics or off-grid applications, up to utility-scale power generation facilities. Using solar PV to power mini-grids is an excellent way to bring electricity access to people who do not live near power transmission lines, particularly in developing countries with excellent solar energy resources. Today, PV is one of the fastest-growing renewable energy technologies, and is ready to play a major role in the future global electricity generation mix.